Can't set headers after they are sent error in express

Question

I've the following 3 files. My error is "Can't set headers after they are sent". I've seen this but I cant figure out which function or callback is causing a write to the headers after they are sent. I've spent immense time on it. please help.

routes.js

"use strict";
var controller = require("./controller");

module.exports = function(app){

  app.post('/master', function(req, res) {
    controller.process(req, function(err, data) {
      if( err ) { 
        return res.sendStatus(400);
      } else {
         res.sendStatus(200);
        }
    });// cb ends here
  });// process ends here
}// route ends here

controller.js

module.exports.process = function(req, cb){
  var jsonBody = req.body;
  var type = jsonBody["strType"]; 
  var id = jsonBody["id"];
  var moment = require('moment');

  if ( !type || !id ) {
    return (cb(true, false));
  }

  if( type === "company" ) {
    Company_strCode = jsonBody["Company_strCode"];  
    jsonBody.lastUpdate = moment().format();
    delete jsonBody["strType"];
    delete jsonBody["id"];
    dbOps.companyUpsert(type, Company_strCode, jsonBody, cb);
    dbOps.normalUpsert(type, id, jsonBody, cb);
    return;
  }

  jsonBody.lastUpdate = moment().format();
  delete jsonBody["strType"];
  delete jsonBody["id"];

  dbOps.normalUpsert( type, id, jsonBody, cb );
} //fnProcess ends

dbOps.js

"use strict";
var keyDef = require('../config/config.json')

var MongoClient = require('mongodb').MongoClient;
var host = keyDef.mongodb.host; 
var port = keyDef.mongodb.port;
var db = keyDef.mongodb.db;
var username = keyDef.mongodb.username;
var password = keyDef.mongodb.password;
var url = "mongodb://"+host+":"+port+"/"+db;

module.exports.normalUpsert = function(type, id, jsonBody, cb){

    MongoClient.connect(url, function(err, db){
        if(err){
            console.log("Mongodb connection error..");
            return cb(true, false);
        }

        db.collection(type).update({"_id":id},{$set:(jsonBody)}, {upsert:true}, function(err){
            if(err){
                return cb(true, false);
            }
            cb(false, true);
        });//func callback
    });// mongoClient callback
};

module.exports.companyUpsert = function(type, Company_strCode, jsonBody, cb){

    MongoClient.connect(url, function(err, db) {
        if(err){
            console.log("Mongodb connection error..");
            return cb(true, false);
        }
        db.collection("Cinema").update({"Cinema_strCompanyCode":Company_strCode},{$set:{"tblCompany":jsonBody}}, {upsert:true}, function(err){
            if(err){
                return cb(true, false);
            }
            cb(false, true);
        });//func callback
    });// mongoClient callback
};

You don't need to return tag in controller, just use callback function without return tag! and don't use return tag anywhere in controller just use callback function!! — Soni Pandey, Dec 14 '15 at 11:21

score 0 · Accepted Answer · answered Dec 14 '15 at 11:45

Inside your if ( type === "company" ) condition, you are calling cb 2 times, causing res.sendStatus to be called 2 times a well. Try a workaround like this if it works for you...

module.exports.process = function(req, cb){
  var jsonBody = req.body;
  var type = jsonBody["strType"]; 
  var id = jsonBody["id"];
  var moment = require('moment');

  if ( !type || !id ) {
    return (cb(true, false));
  }

  if( type === "company" ) {
    Company_strCode = jsonBody["Company_strCode"];  
    jsonBody.lastUpdate = moment().format();
    delete jsonBody["strType"];
    delete jsonBody["id"];
    dbOps.companyUpsert(type, Company_strCode, jsonBody, function (err, data){
      if (err)
        return (cb(true, false));
      else
        dbOps.normalUpsert(type, id, jsonBody, cb);
    });
    return;
  }

  jsonBody.lastUpdate = moment().format();
  delete jsonBody["strType"];
  delete jsonBody["id"];

  dbOps.normalUpsert( type, id, jsonBody, cb );
} //fnProcess ends

or I would prefer something like this :

module.exports.process = function(req, cb){
  var jsonBody = req.body;
  var type = jsonBody["strType"]; 
  var id = jsonBody["id"];
  var moment = require('moment');

  if ( !type || !id ) {
    return (cb(true, false));
  }

  jsonBody.lastUpdate = moment().format();
  delete jsonBody["strType"];
  delete jsonBody["id"];

  if( type === "company" ) {
    Company_strCode = jsonBody["Company_strCode"];  
    dbOps.companyUpsert(type, Company_strCode, jsonBody, function (err, data){
      if (err)
        return (cb(true, false));
    });
  }

  dbOps.normalUpsert( type, id, jsonBody, cb );
} //fnProcess ends

Can't set headers after they are sent error in express

1 Answers1